Transfer mechanism for removing workpieces from a tank filled with liquid



y 27, E. STENGEL 3 TRANSFER MECHANISM FOR REMOVING WORKPIECES FROM A TANK FILLED WITH LIQUID Filed March 8, 1968 United States Patent US. Cl. 214-130 4 Claims ABSTRACT OF THE DISCLOSURE Conveyance of heated workpieces from a tank filled with liquid, e.g. inductively heated and quenched metal workpieces, is usually effected by the intermittent rotation of spiders carrying the workpiece, the hardened workpiece being transferred to a conveyor belt for removing the workpiece from the bath.

The invention provides an arrangement for transferring the workpiece from the spider which has a minimum of moving parts within the liquid bath, and which includes a cranked lever adapted to carry the workpiece at one end, and which is suspended in such a manner that the workpiece may be swung by the cranked lever up and out of the liquid bath.

This invention relates to a transfer mechanism for removing workpieces from a tank filled with a liquid and delivering the same at a point outside the liquid-containing tank. Such a mechanism is required for instance in induction heating plant for the purpose of removing heated, e.g. inductively heated, workpieces from a quenching bath therefor.

In such plant, for example inductively heated workpieces such as camshafts for internal combustion engines may be chucked up between centres in a pair of spiders. By movement of the spiders through predetermined angles, the work is conveyed into the heating range of an inductor and after having by further movement of the spiders into a quenching bath. After having been hardened by the action of the quench the workpiece must be released by the spiders and transferred to a suitable transfer mechanism adapted to convey the workpieces out of the tank containing this quenching liquid.

It has hitherto been the practice to use endless chain conveyors for this purpose. These receive the hardened workpieces that have been deposited in the quenching bath and by their continuous motion carry them up to the return point of the chain which is situated above the level of the liquid outside the quenching tank.

Conventional equipment of this kind has some major disadvantages. Thus, chain conveyors occupy considerable space, and also comprise a large number of interlinked component parts resulting in a large number of points where faults may arise. Furthermore, owing to its continual immersion in the quenching liquid it is also continuously exposed to corrosion by the quenching liquid, and is thus liable to suffer considerable damage.

It is the object of the invention to provide transfer mechanism which avoids at least to some extent such disadvantages.

The invention consists of a transfer mechanism for removing workpieces from a tank filled with a liquid and delivering the same outside the liquid, comprising a cranked lever provided at one end with a work-receiving means, suspending means for the said cranked lever comprising a first pivoted arm pivotably attached to the elbow been inductively heated is then conveyed of the cranked lever and a second pivoted arm pivotably attached to the end of the cranked lever remote from the end thereof having the said work-receiving means whereby the cranked elbow is suspended by the said first and second pivoted arms, and drive means for swinging at least one of the said pivoted arms whereby the cranked lever is moved so that the said work-receiving means is conveyed along a path between a lower position and a relatively higher position.

The work-receiving means is said end of the cranked lever.

In a particularly useful embodiment of the invention the cranked lever and the said first and second pivoted arms pivotably linked thereto are so contrived and relatively arranged that the workpiece resting in the fork of the cranked lever will be conveyed by the swinging of the cranked elbow along an approximately rectilinear path when the swing arms are deflected through an angle of at least 60 degrees. For limiting the amplitude of the to and fro movements of the cranked lever, limit switches may conveniently be provided.

An embodiment of the invention used in association with inductive heating and hardening plant is hereinafter described and illustrated in the accompanying drawing, which is a schematic elevation of the plant embodying the invention.

Referring to the drawing, the central component of inductive heating plant is an intermittently-rotatable spider 1 with stopping stations 2, 3 and 4.

The workpiece is held in position W between centres not shown, at the stopping station 2 after having been delivered by a conveyor chain 5 to a workpiece receiving member 6. By rotation of the spider 1 through an appropriate angle, in the illustrated embodiment an angle of the workpiece arrives in position W where in the drawing the stopping station 3 is located, within the heating range of inductor 7. As soon as the workpiece under the inductor 7 has been raised to hardening tern perature, the spider 1 is again moved through a corresponding angle to convey the workpiece into the quench liquid contained in tank 10.

After having been quenched in position W which in the drawing corresponds to the stopping station 4, the workpiece is released by the spider 1 and deposited on a transfer mechanism according to the invention to be removed thereby from the tank 10 containing the quench liquid.

The transfer mechanism according to the invention con sists of a cranked lever 13 which at one end is formed with a fork 12 for the reception of the workpiece.

At the stopping station 4 the quenched workpiece in position W must first be released by the centres before being conveyed out of the quench liquid. This can be done if the forked end 12 of the cranked lever 13 is located under the stopping station 4 at the instant the transfer of the workpiece is to take place. The cranked lever is pivotably linked to two swing arms 14 and 15 each mounted at one end on a separate rotatable shaft 16 and 17 respectively. The swing arm 14 is pivotably linked to the elbow and the swing arm 15 to the arm 13 of the cranked lever remote from the fork 12. One of the shafts, for instance the shaft 16 may be provided with drive means. The drive means is activated as soon as a workpiece has been deposited on the fork 12 of the cranked lever 13 and rotation of the shaft 16 causes both swing arms 14 and 15 to swing in the direction of the arrow 18 through an angle of about 60. The construction and disposition of the swing arms 14, 15 and of the cranked lever 13 is preferably such that the workpiece resting in the fork 12 will be conveyed along an approximately rectilinear path indicated by the dot-dash line 19. Only the final part of this path is arcuate, thereby causing the preferably a fork on the workpiece to drop out of the fork of its own accord and to be deposited on a slightly inclined chute 20. In order to prevent the workpiece from prematurely falling out of the fork because of unskilful control of the transfer mechanism or of any other accidental occurrence, the chute 20 is rearwardly extended into the quenching tank. Since the end of the fork 12 moves over the chute extension in close adjacence thereof, the workpiece is prevented from falling back into the quench liquid.

In the final position of the lever mechanism, the swing arm 14 operates a switch 21 which reverses the direction of rotation of the shaft 16 and thus causes the fork 12 to return into its previous position under the stopping station 4. Upon reaching this position a further limit switch 22 is arranged to stop further movement of the arms. The operating speed of the transfer mechanism must be st chosen that the time required for a to and fro motion or the fork is always less than the indexing intervals of the spider to enable the fork 12 to be underneath the stopping station 4 before the next workpiece is released by the spider in position W The novel form of construction of the proposed transfer mechanism is particularly useful for the described purpose because the number of articulations and bearings immersed in the quenching bath is small and the drive means for the transfer mechanism is above the level of the quench liquid 11. Consequently bushings that require sealing in the wall of the tank are not needed. Moreover, the workpieces may be conveyed along a direct path to their destination in a very efficient manner, the acceptance and delivery of the workpiece being completely automatic.

What is claimed is:

1. A transfer mechanism for removing workpieces from a tank filled with a liquid and delivering the same outside the liquid, comprising a cranked lever provided at one end with a work-receiving means, suspending means for the said cranked lever comprising a first pivoted arm pivotably attached to the elbow of the cranked lever and a second pivoted arm pivotably attached to the end of the cranked lever remote from the end thereof having the said workreceiving means whereby the cranked elbow is suspended by the said first and second pivoted arms, and drive means for swinging at least one of the said pivoted arms whereby the cranked lever is moved so that the said work-receiving means is conveyed along a path between a lower position and a relatively higher position.

2. A transfer mechanism according to claim 1, in which the said work-receiving means consists of a fork on the said end of the cranked lever.

3. A transfer mechanism according to claim 1, in which the cranked lever and the said first and second pivoted arms are so contrived and relatively arranged that the workpiece resting in the work-receiving means of the cranked lever is conveyed along an approximately rectilinear path when the swing arms are deflected through an angle of at least 60 degrees.

4. A transfer mechanism according to claim 1, in which there are provided limit switches adapted to control the amplitude of the to and fro movement of the cranked lever.

References Cited UNITED STATES PATENTS 2,429,525 10/1947 Rawlinson et al. 214-130 X ROBERT G. SHERIDAN, Primary Examiner.

US Cl. X.R. 214-91 

